Vehicle suspension.



B. LIEBOWITZ. VEHICLE SUSPENSION. APPLICATION FILED mm. 27, 191;.

Patented Aug. 4, 1914.

R 0 I N E V W 2% flt rit illlliilhl ll @Llllh nnnmmrititauaowrrz, 0}? new "roan, n. Y.

VEHICLE SUEPENSIGN.

To all whom it may concern:

Be it known that I, BENJAMIN Linnowriz, a citizen of the United States, residin in the city, county, and State of New Yoric, have invented certain new and useful Improvements in Vehicle Suspensions, of which the following description and claims constitute a specification and which is illustrated in the accompanying drawin This invention relates to means for flexibly mounting the body of a vehicle upon the running gear thereof.

The ob ect of this invention is to provide a suspension which will render the suspended body approximately non-oscillatory by the employment of a mechanism constructed to check the free vibrations of the body relative to the rut ninp,- gear Without increasing the forced vi rations thereof and which poi forms its functibns satisfactorily without roquiring the aid of supplementary devices.

The principle of this invention in whatever, mode it is embodied is as follows: The suspended body is rendered approximately non-oscillatory by means of frictional do vices which permit of rapid upward motions of the running gear relative to the body without imposing objectionably large forces on said body and which do not appreciably hinder the downward motions of the running gear relative to the said body.

The accompanying drawing is a diagrammatic sectional view of one form of a .mecha nism embodying my invention.

In practice a plurality of these devices are used to support the body, but here only one is shown.

1. represents the running gear of the vehicle, and 2 represents the body.

3 is a cylinder which is rigidly or otherwise connected to 2, and i is a piston which slides in 3 and which is rigidly or otherwise connected to l. The arrangement of connecting etc 2 and to 1 may also be used.

12 is alargc chamber in communication with cylinder 3 through opening 14.

3 and 15! are filled with gas under the proper pressure to secure flotationa] support of the-body 2.

8 is a chamber, supplied by the source 20, containing gas under a higher pressure than the pressure in 12.

9 is a space containing gas under a lower pressure than that in 12. The most convenient gas to use is air, and space 9 may then conveniently be the atmosphere.

Specification of Letters IPatent; Application filed February er, 1911. Serial No. emote.

ltatcnted King. a, 191d.

10 is a small hole in the wall of the cylinder in communication with space 8. Normally 10 is covered by the piston but when the piston passes inward be yond a predetermined position, which I shall designate as position A in the remainder of the description, 10 is uncovered by slot 6, which isin communication with l of cylinder. Hence cylinder 3 is put into throttlcd iwmmunication with the high pressure space 8 when the piston passes inward beyond position A.

11 is another small hole in the cylinder 3 in conin'iunication with low pres sure space 9. Normally, 11 is covered by the piston, but when the piston passes outward ieyond a predetermined position, which will hereafter be designated as position 13,, hole 11 is uncovered as by means of sloth. If opening, 11 is put higher, then slot 5 is not necessary. l'lcnce cylinder 3 tln'ottled communication with low pressure space 9 when the piston passes outward. be yond position B. V

The intrmluction of friction into vehicle suspcnsioi'is has been very much misuudcrstood and this inisiinderstanding has been one of the chief causes of the failure of suspensions hcretotore devised to operate at moderately high or high speeds without eniploying highly deformable trends. The 'tunctimi which friction in vehicle suspensions has to perform is to render the suspended systcm uon-oscillatory, 1'. e., to check the tree vibrations of the body. Now in any vehicle, as the runuinggear moves upward relative to the body,-tlic unbalanced forces impressed on the body are the elastic restoring force plus the and when the ruuninn'pear moves downward relative to the body the unbalanced forces acti in; on the running-gear arc gravity plus the total elastic force 01' the suspension minus the friction of the suspension. Be cause of these facts, two dctriinei'ital clients are produced by the friction when it is not properly applied; (1) the forces impressed on the body b' the upward motion of the runniugpear ecomc objectionably large, and (52) the quick descent oil an n wardlf, displaced wheel back to the roallbet, whic 1 quick descent is necessary for the preservation of traction, is hindered. That is to say,

wall of the the friction, whose function is to check the free vibrations of the body, increases to a very objectionable extent the forced vibrahi gh pressure the interior is put into.

friction of the suspension large time of the hotly, and the some time lowers the sa'tte l'lniting speed of the vehicle by retarding; the descent of an. upwardly displaced. wheel to the road-bed, u s the friction is properly applied. All tional moons which possess the characteristic that their friction increo see rapidly with the velocity of the running-gear relative to the body will cause these detrimental effects. Such are, for example, liquid dash-pots,and the internal friction, (akin to viscous fricev tion in liquids) inherent in steel springs. Frictional means which do not introduce these detrimental eiiccts are gaseous clashpots and rubbing surfaces, for example. Such frictional means will hereinafter be designated as quick-acting frictional means. Hence, by the e:\;pression quichacting -hcict-ioned means is to be understood frictional means which permit rapid upward motions of the running-gear relative to the body without imposing objcctionably forces on. the body and which do not hinder to an objectionable extent the downward motions of the running-gear relative to the body. This feature of the employ ment of quick-acting frictional means in my invention to render the sgspended system aperiodic, or approximately so, and keep ng all other frictional ellects negligibly small throughout the normal range of piston posi tions, is one of the most important aspects of my invention.

My invention is regarded as including all types of quick-acting frictional menus used in connection therewith. That'is to say, do not limit my invention to the use therewith of any particular quick-acting frictional means. The means which 1 prefer to use, however, is of the gaseous clash-pot tyne.

I obtain the friction on this principle,

ill hilt? form of my device shown in the draw ing by constricting opening 14- to the proper extent and by properly proportioning the cylinder and the chamber 12. For slow motions such as would be due to the free oscillations of the body, gas is forced through opening 14., thus introducing the desired friction to check the free oscillations of the body after the first swing or so, iii the various parts are properly proportioned. For rapid motions,= however, when the friction would bccomevery large, it the medium were imcompressible (as in liquid dashpot-sl, very little gas passes through opening 1 1'. while the compression of the gas, in

the cylinder becomes correspondingly larger. Thus the frictional force introduced by this means can. never exceed the compression forceof the gas in the cylinder 3, and since, by proper proportioning of the cylinder, this woprcssion force can'be made as small as I I. for ordinary displacements, the

tunnel forces introduced by this means can oasi 1y be kept within required limits for of opening 1% will depend on the required limits of displacement. In other words, this type of frictional element introduccs the friction only for slow-motions of the body relative to the molding-gear, and it. is only for such slow motions that friction is required.

Referring again to the drawing, the size ratio of the volume of chamber 12 to volume'oii the piston displacement, the larger this ratio the larger the holes can be, for thenthe restoring. force per unit displacement is smaller, hence the friction need be less. For certain classes of service, however, a large restoring force per unit displacement is permissible, and therefore, this invention is regarded as including all sizes of chain ber 12 in communication with cylinder 3, including no chamber external to the cylinder. in this latter case some other frictional means must be used than the internal aseous dash-pot describe l, such as external air dash pot, or rubbing surfaces.

As shown in the drawing, opening ll is placed to he closed by the piston before it reaches the top, so as to cushion extreme displacements. This opening is shown single opening but it. can consist, of several openings, or of several. sets. of'opem ings successively closablc by the piston as it moves inward, so that forsmull displace ments in the neighborhood of the equilibrium position, chamber and cylinder is less'restricted, and greater benefit from the presence of. the large chamber can then be derived.

To limit outward displacements, some form of stop is necessary. In practice, it is most convenient to incorporate this stop in the suspension proper or in the external frictional element if one is used.

communication between The arrangement of high and low pressure spaces, holes and slots is sition B, independently of the load on the vehicle. For, if there is any tendency for piston 4 to remain inward beyond position A, such as may be due to. the addition of load to the vehicle or to leakage, opening 10 will remain uncovered and allow gas to pass from chamber 8 to cylinder 3 till the pressure on piston 4 is $11 'ciently increased to raise the body high enough to cover opening 10 again. Position A will then be the equilibrium position from which displacements of piston 4 will occur. In the same way, if there is any tendency for the piston 4 to remain outward beyond B, opening 11 will remain uncovered, and gas willbe expelled from the cylinder till the body is lowered sufficiently for opening 11 to be closed again; Position B will then be the equilibrium position. When position A is the equilibriunr position the movement of I I to keep the equilibrium POSIlJlOXl of the body of the ve hiole somewhere between position A and pothe piston due to the wheels passing over the inequalities of the road surface, will uncover opening 10 more than opening 11, hence the equilibrium osition will tend to move toward position Similarly, when position B is the equilibrium position, it will tend to move toward position A.- The latter tendency is increased by leakage, hence it is desirable to have the areas of holes and differences of pressure so pro ortloned that gas is admitted more re idly than it is expelled through the oles. Hence, the equilibrium position of the body will always be between position A and osi- 8051 B, independently of the weight the In the drawing, when the top of the piston touches the line A, the piston is in position A, and when it touches the line B it is in position B. The uncovering of holes and 11 as the piston moves through its ran e can not affect the main action of the mec anism because changes in pressure due to the passage of gas into or out of the cylinder through the holes will be comparatively slow. r

By the term body of the vehicle or, body is to be understood all that mounted on the suspension, and by the term running-gear is to be understood all the rest of the vehicle. The terms non-oscillatory and aperiodic as used in this specification are synon mous, and are to be understood to inc ude ap roximatelv aperiodic and approximate y non-osci latory. Chamber 12 will be referred to in the claims as the additional chamber. The cylinder 3 and the piston 4 will be referred to as the supporting-cylinder and the supportingpiston, respectively. f a

I am aware that pneumatic and hydropneumatic suspensions, having the same object as this invention, have previously been devised, but these prior inventions either do not consider friction at all, or they do not apply the friction properly when they do consider it, and they have failed very largely because of this fact. I am the first, so far asI am aware, to apply the friction correctly, and for the proper purpose, and in addition, my mechanism for meeting load changes is new, hence l/Vhat I claim is: t

1. In a suspension for vehicles the following elements in combination: a supportingpiston sliding in a supporting-cylinder; gas in said supportingcylinder under the proper pressure, normally, to secure flotational support of the body of the vehicle; a high pressure spacein communication with a hole in the wall of said supporting-cylinder, which hole is normally covered by said supporting-piston, but which is uncovered by a slot in said supporting-piston when said. supporting-piston passes inward be- \meu yond a predetermined inward in communication with a position, said slot being in communication with the interior of said supporting-cylinder; a low pressure space in communication with another hole in the wall "of said supportingcylinder, which hole is normally covered by said supporting-piston, but which is uncovered when said supporting-piston passes outward beyond a predetermined outward position, said inward and outward positions being not coincident, high and low referring to the normal range of pressure in said supporting-cylinder; a gas supply for maintaining the pressure in said high pressure space within the proper range; and quickacting-frictional means adapted to render the suspended system non-oscillatory or approximately so.

2. In a suspension for vehicles, the following elements in combination: a supporting-piston sliding in a supporting-cylinder; an additional-chamber 1n communication with said supporting-cylinder; gas in said additional chamber and supportingcylinder under the proper pressure, normally, to secure fiotational support of the body of the vehicle; a high pressure space hole in the wall of said supporting-cylinder, which hole is normally covered by said supporting-piston; a slot in said supporting-piston which is in communication with the interior of the said supporting-cylinder and which uncovers said hole when said supporting-piston passes inward beyond a predetermined inward position; a low pressure space in com munication with another hole in the wall of said supporting-cylinder, which hole is normally covered by said supporting-piston but which is uncovered when said supportingpiston passes outward beyond a predetermined outward position, said inward and outward positions being not coincident, high and low referring to the normal range of pressure in supporting cylinder, a gas su ply for maintaining the pressures in said high pressure space within the proper range; and qlliclr-acting-fricthmal means adapted to render the suspended system non-oscillatory or approximately 50.

3. In a suspension for vehicles, the following elements in combination: a supporting-piston sliding in a supportin 'cylin- (:ler; an additional-chamber in, communication with said supporting-0y]inder through ports in the wall of said supporting-cylinder, which ports are closed or almost closed by said suprmrting-piston before it reaches its inward limit of positions: gas in said additional chamber and supporting-cylinder under the proper pressure, normally to secure flotational support of the body of the vehicle; a high pressure space in communication with a hole in the wall of said su porting-cylinder, which hole is normally tion with a liole in the wall oi said supportcovered by said supporting'pistong a, slot in said supporting-piston which is in communication with the interior of said supportingcylinder, and which uncovers said hole when said supporting-piston passes. inward beyond a predetermined inward position; a low pressure space in COlIllQllllIl'l'lHtlOIl with another hole in the wall of said supportingcylinder, which hole is normally covered by said supporting-piston, but which is uncovered when said support lg-piston' passes outward beyond a predetermined outward position, said inward and outi'ard position; being not coincident, high and low referring to the normal range of pressures in said supporting-cylimler; a gas supply for maintaining the pressure, in said nigh pres sure space within the proper range; and quic r-acting-irictional means adapted to render the suspended system non-oscillatory; or approximately so.

i. In a suspension for vehicles the following elements in combination; a supporting pisi on sliding in a supporting-cylinder; an additionai-chamber in communication with said suppciting-cylinder through openings in the wall of said supporting-cylinder, which oper ing saare completely or nearly con'ipletely closed bys'aid; supporting-piston heforeit reaches its limit or inward positions, gas in said additional chamber and supper-ringcylinder under the proper pressure normally, to secure flotational support of the body of the vehicle: a high-pressure space in communication with a hole in the wall of said support ing-cylinder, which hole is normally covered by said supportingpiston; a slot in said supporting-piston which is in communication with the interior of said supporting-cylinder and which uncovers said hole when said supporting-piston passes inward beyond a predetermined inward position; a low pressure space in communication with another hole in the wall of said supporting'cylinder, which hole is normally covered by said supporting-piston, but which is uncovered when said supportingpiston passes outward beyond a predetermined outward position, said inward and outward positions being not coincident, high and low referring to the normal range of pressures a gas supply for maintaining the pressure in said high pressure space within the proper ange.

in a suspension for vehicles, the following elements in (:omhiimtion; a supporting piston sliding in a supporting-cyiinder; an additional-chambcr in communication with said supporting-cylindcr: gas in said additional chamber and der the proper pressure, fiotational support of the hicle; a high pressure space body oi. the" vem communicain said supporting-cylinder; andv supporting-cylinder unnorma llv. to secure LIMLQOIS ing'cylinder, which hole is normally covered by'said supporting-piston; a slot in said supporting-piston which is in communication with the interior of said supporting cylinder and which uncovers said hole when said supporting-piston passes inward beyond a predetermined inward position; low pressure space in communication with another hole in the wall of said supportingcylinder, which hole is normally catered by said supporting-piston; but which is uncorered when said supporting-piston passes outward beyond a predetermined outward position, said inward and outward positions being not coincident, high to the normal range of pressures in said suporting-cylimlerg and a gas supply for maintaining the pressure in the high pres sure space within the proper range.

6. In a suspension for vehicles, and for other applications, the following elements in combination; a piston sliding in a cylinder; gas in said cylinder under the required normal pressure; a high prcssure spzute in com munication with a hole inthe wall of said cylinder, which hole is normally covered by said piston; a slot in said pisto which is in comn'iunicatiou with the interior of said cylinder, and which uncovers said hole when said piston passes inward beyond a predetermined inward position; a low pressure space in communication with another hole in the wall of said cylinder, which hole is normally covered by said piston, but which is uncovered, when said piston passes outward beyond a predeternined outward position, said inward and outward position being not coincident, high and low referring to the normal range of pressures in said cylinder, and a gas supply for maintaining the pressure in the high pressurespace 1thin the proper range.

7. Ina suspension for vehicles, the following elements in combnation; a supportingpiston sliding ina suppcrtingwylindcr; an additionul-chamber in communication with said supportlug-cylinder; gas in said additional-chamber and supporting-cylinder under the proper pressure. normally, to so cure flot'atioual support of the body of the vehicle; a high pressure space which is put into throttlcd communication with said sup porting-cylindcr when said sopport'ing pis ton pass-cs inward beyond a pl'tlltltl'lllllK"i low pressure space which inward position; a

is put into throttled comnumication with and low referring said s'upporting-cylindci when said sup 'icrting-p'iston passes outward beyond a rcdo,- termined outward position. outward positions being not coincident. high and low referring to the normal range of pressures in said supp i i-tiire-cylinderz a gassupply for maintaininputhe prcs ul'e oi the high pressure chamber within the proper range; and quick-art )(JL-lOllzil means said inward aim! adapted to render the suspended syslein nonoscillatory or approximately so.

8. in a suspension for vehicles, the followin; elements in ronibination; a supportingpiston sliding in a supportingwylinde' an additionaI-rhamber in coinnmniration with said sup i i-tiiig-cyli11(ler through openings in the wall of said supporting-rylinder, which openings are completely or nearly completely closed by said snpporting-piston before it reaches its inward limit of positions; gas in said additional chamber and supportingmylinder under the proper pres sure, normally, to secure llotational support of the body of the vehicle; a high pressure space which is put into throttled communiration with said slipportiiig-cylinder when said supporting-piston passes inward beyond a predetermincd inward position; a low pressure space which is put into throttlrd eonininniration with said supporting eylinder when said simporting-piston passes outward beyond a predetermined outward position, said inward and outward positions being;- not coincident, high and low referring to the normal range of pressures in said supporting cylinder; a gas supply for maintaining thepressure in the high pressure space within the proper range; and quick-acting- :l'rirtion'al means adapted to render the pended system non-oscillatory or approximately s0.

9. In a suspension for vehicles, the .lo1l0w ing elements in combination; a supportingpiston sliding in a supporting-eylinder; an ltllllltltllljll chamber in restrieted communication with said supportingwylindcr whereh the 'HU )er amount of friction is intro duced to rei'ider the suspemled system nonoscillatory or approximately so, all other frictional forces being small compared with the gtl:5 pl't?5Slll't .lorres tl'n'oughout the normal range of piston positions; gas in said additional chamber and su )porting-(:yliuder under the proper pressure, normally, to secure llotational support of the body of the vehicle; a high pressure space which is put into throttled coinnninication with the said supportinn-cylinder when said su iporting piston passes inward beyond a predetermined inward position; a low pressure space which is put into throttled rommuniealion with said supporting-cylinder when said supportingypiston passes outward beyond a predetermincd position, said inward and outward positions beinp not eoincident, high and low reii'erring to t-llJIlUllIltll range of pressures in said supportingeylinder; and a gas supply for maintaining the pressure in the high pressure space within the proper range.

iln testimony whereof, I have hereunto allixed my signature in the presence of two subscribing witnesses.

BE NJA MIN LIEBUWl'l /J. \Vituesscs Linen, B. Rummy, JAtJOB N. lasco.

Kit" 

